The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
LTE and LTE-Advanced have been mandated as radio access technology (RAT) for public safety (PS) networks (PSN). Public safety covers a variety of different security functions from safeguarding citizens against natural disasters, to countering terrorism and organized crime, etc. In PS networks mobile devices may communicate directly with each other in a device-to-device (D2D) mode or in a so called direct mode.